Nyczbubba

So I've been having trouble with my intake manifold with air leaking from the lower intake manifold and from the runners of the TPI setup. The car has so many air leaks that the RPM's at Idle stay roughly around 2000 rpm. When I spray gum cutter into the seams the engine sucks it up and the rpm's bog. I bought the car last year from someone and he says it's a 93' LT1 motor with the TPI setup. Is this possible? Would it fit? So I bought someone else's tpi setup off of a 305 tpi. The lower manifold doesn't match up and it doesn't fit. So I was wondering are all TPI setups the same or they different?

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pics-

RBob

iTrader: (1)

There are quite a few differences between the various TPI intakes. The MAF units don't have the port for the MAP sensor. The MAF '85 - '88 units are set up for a cold start injector. While the '89+ units don't.

The Corvette TPI bases used the original SBC intake manifold bolt pattern (4 center bolts) While the f-body bases changed in either '86 or '87 to the newer bolt angle pattern.

An LT1 engine uses the Vortec intake manifold bolt pattern. To which there are TPI bases available for.

I'm am quite sure that there are other differences. I recall that even the plenum shape changed from time to time.

RBob.

Nyczbubba

So best fitting one would be a newer one from after 89'? The one that I bought was from an 86'. Which TPI setups would fit on an LT1?

vetteoz

iTrader: (13)

Possible with work but unlikely
Is the dist at rear or front?


None
unless you want to start drilling holes

Tuned Performance

iTrader: (92)

Rbob already stated you would need a vortec tpi intake. Scoggin dickey, edelbrock and at one time accel made one for linginfelter.

http://www.hotrodlane.cc/PDFFILES/TPIStory.pdf
http://www.summitracing.com/parts/ed...FeeDQgodMHkATg
https://sdparts.com/details/scoggin-...-center/sd3816

vetteoz

iTrader: (13)

Still wouldn't work because while LT1 heads have the Vortec bolt pattern , they still have reg SBC ports that won't match to the tall , thin Vortec ports
If you wanted a TPI on a LT1 ( heavens knows why ) then you just use a TPI base , re-drill the holes to LT1 pattern and plug the dizzy hole at rear

Nyczbubba

The distributor is in the back. See I don't want to make it a TPI setup. I'm just trying to fix the problem with the air leak. So the guy is swearing he put an LT1 block from a 93 z28 in the car but, put a 92 z28 TPI setup in. I don't understand why he would do that. Is there a way to tell if it's a LT1 motor or not? I did buy headers for this car for a 92 Camaro and the headers lined up perfectly. Unless the headers for a 93 and 92 are the same I'm going to say that he just lied to me about it being a LT1 motor.

Oh to add I just found out that I bought an 86' TPI setup from someone and ended up wasting my money I guess because I guess there was no chance of that fitting.

vetteoz

iTrader: (13)

Where does the top water hose from the radiator go to?
The water pump or the intake manifold ?

If as we suspect you have a NON LT1 engine then it should work fine

Jim85IROC

iTrader: (2)

Does it have a distributor at the back of the motor? If so, it's not an LT1. For a while Accel did make a TPI baseplate for the LT1, but they are rare.

Nyczbubba

I would have to check on where the water hose is.

The 86' tpi doesn't fit on the 89-92 I heard is this true?

vetteoz

iTrader: (13)

Fits perfect.
There are minor differences but nothing that physically stops a early TPI being used on a later engine or vise versa

Nyczbubba

Ok just spoke to my mechanic, he said the center bolts don't line up. Would I be able to drill into the manifold so that it will be able to bolt on? So again I'll explain that I am trying to run the 86' tpi setup on the 92. I can use the same plenum even though that the MAF uses the cold start injector??

vetteoz

iTrader: (13)

Get a better mechanic ;or at least one that can think a bit
The bolt angle is different;
you just file out those 4 center holes on the base a little until the bolt fits and maybe use a washer under those 4 bolts
Some aftermarket intakes come with those 4 holes elongated so the one intake will fit both early or late heads

Sure
You only swap over the base and reuse all your other existing parts
Your late year runners will seal the cold start injector hole in the early base anyway

vetteoz

iTrader: (13)

You still haven't worked out if you have a LT1 engine or not yet?

Nyczbubba

The distributor is in the back so I'm guessing it isn't

Tuned Performance

iTrader: (92)

If it has the accel intake you can have the distributor in the back look at the timing chain cover and water pump.

Tuned Performance

iTrader: (92)

or are you talking about this is a Lt1 from a 70-72 ?
sounds like you just need to elongate the 4 inner bolt holes on the intake

Nyczbubba

Yeah the center bolts are not matching up. So I wouldn't have any issues mounting and running an 86 tpi setup that has the different MAF. Just drill into the manifold and mount?

Tuned Performance

iTrader: (92)

yes just elongate the 4 inner holes and you can use the earlier intake. all the rh runners are the same for tpi but the lh is specific to the plenum 85-88 have a tube for the egr passage on the lh runner. If your lh runner has the spot for the csi but your rail does not have the ninth injector buy a block off kit and check the plenum for the egr hole you can tap and make a npt plug fit so you will not have a vacuum leak or use a expansion plug.
if you have a maf equipt car you will ned to be running a 89 tpi calibration to aid with cold starting. with out pictures of your parts its hard to say what your dealing with.
http://www.ebay.com/itm/Camaro-Firebird-TPI-Cold-Start-9th-Injector-Block-Off-Delete-Kit-/380623518915?pt=Motors_Car_Truck_Parts_Accessories&hash=item589eedfcc3&vxp=mtr

vetteoz

iTrader: (13)

You say you already have a working TPI setup ;
why would you not only swap out the problem causing part ( the base ) and then reinstall the rest of your existing TPI setup ?
No need for changes to anything

You have not stated WHAT TPI setup is your car.
Was the car originally a TPI car or a TBI car ?

Just because it is a 92 , if it was swapped to TPI ,nothing to say someone has not installed the earlier MAF TPI setup instead of a MAP TPI that the 90 -92 came from the factory with

Nyczbubba

It leaks from the lower intake manifold and the upper plenum. The tpi setup is currently a 92 tpi setup. Originally it was a TPI and still is a tpi. I just am trying to get the car to run smoothly. Also currently has SLP runners on it too. I rather just change everything because air leaks are coming from everywhere.

TTOP350

iTrader: (8)

Take it apart, clean all your gasket surfaces and reassemble properly with correct sealants and gaskets. Don't try putting the older TPI parts on it. Its a waste of money and there are a few differences that will cause more problems than it would fix.
I will say if you have org injs, icm or anything like that, they could be going bad. Test those things..

Nyczbubba

*UPDATE* Ok so I found out that the intake manifold that was installed is an aftermarket intake manifold (Edelbrock) and running SLP runners. The gasket that was put on was for a stock gasket. Is it possible that the Edelbrock manifold doesn't seal up right for some reason, or maybe warped? New gaskets and cleaned the surface and still leaks. Please bare with me as much as possible. I will get as much info as I can. Thanks for all the help everyone providing me.

Nyczbubba

Goes right into the intake manifold.


Attatched is the only pic I have the motor right now. I hope this helps.

InfernalVortex

iTrader: (4)

Then its not a 93 LT1.

vetteoz

iTrader: (13)

Where are the vac leaks at now; where the runners connect or where the base connects to the engine?

Did you consider putting a straight edge across the base surface and either end of the runners while you had it all apart to confirm they are straight?

Nathaniel92

Well? I would like to have know the outcome of this. Currently my Scoggin Dickies intake manifold has a massive vacuum leak. I used the Vortec heads gasket, proper torquing, etc. Really don't think it is human error on my end, won't know for sure until I take the top end off and find out, lol. Are SD intakes notorious for needing machining done right out of the box?

Abubaca

iTrader: (3)

No, they can sure use a little help performance wise, but as for fit and finish I don't think many people have had any issues. Are you sure you have the proper runner gaskets on the proper side? You can get 'em backwards and sometimes have big leaks. ...it may only be with certain runners and certain gaskets, etc. etc., but there's a thread on here somewhere showing pictures. I think it's the 9th injector hole on the driver side. Regardless...check the EASY parts first before taking the whole manifold off.

Nathaniel92

I might have? I used a Snap On Smoke Leak Detector. Made it kinda obvious to what's going on. I'll follow up on this here in a few weeks after I take it apart. I really hope like hell it is on me and not SD. But there is no other way than removing it at this point to find out who screwed up, lol. Smoke don't lie.

Abubaca

iTrader: (3)

Is it just one leak or multiple places? ....and where?

Nathaniel92

It's like one massive leak coming out from the drivers side of the entire length of the manifold. Just on the one side, and seeping through into the valve cover and also running off into the rear valley. Idk, that's whats got me thinkin' the manifold might need to be machined? The heads aren't shaved.. I can't imagine I'd make a blunder like that, but ya never know. Only vacuum leak on the motor.

bigbrother

as much as I hate resurrecting a dead thread, we've got the same thing with an SDPC intake as well (vortec heads). It's got a serious vacuum leak at the intake base. somewhere What did you find out was the fix?

Nathaniel92

It was the intake. It wasn't exactly flat, had to mill it by 0.000nothing, lol. Can’t recall all the details. Wasn’t a huge deal, or at least my guy didn’t make one out of it. It’s a common problem with that manifold from what I’ve read.. and I paid $500 for that damn thing like 6 years ago! Car came out bad ***, it was fun. If I had to do it all over again I would’ve waited and found Holly stealth ram (whatever it’s called) they quit making. Not just because of that 1 of many little issues.. simply for the horse power!

bigbrother

oh boy, my brother will be thrilled to hear that he has to pull the manifold and send it out to be milled. That will also make the jackass working on it's day getting to bitch about using aftermarket parts.

KyleF

Find someone else to work on it. There is a whole industry built around modifying cars and a culture that has persisted for close to a century now. Go to a mechanic that actually enjoys his job and you will probably get better support.